| According to properties of anaerobic effluent from soybean further processing wastewater, the MBBR-SA process consisting of moving-bed biofilm reactor, settling tank and anaerobic tank was designed and used to treat the anaerobic effluent from soybean further processing wastewater. By comparing to CAAC (Countinue Aerobic-Anaerobic Coupled) process and choosing the better combination property process, the work has been done that included designing pilot-scale process flow and reactors as well as choosing models of appliances and attachments. In order to accelerate the process start-up, increase NH4+-N removal efficiency and realize better effect of excess sludge reduction, aerobic degradation strains were screened according to anaerobic effluent characteristic and dominant aerobic degradation microbic communities were constructed. The research results were as follow:(1) By comparing treatment performance under different HRT and reflux ratio, the optimal HRT and reflux ratio were 1.68d and 0.75 respectively. The treated effluent levels of COD, NH4+-N, TN were 59.5 mg/L,6.2 mg/L,6.8 mg/L respectively and met ClassⅡstandard, Class I B standard and ClassⅡstandard of discharge standard of pollutants for municipal wastewater treatment plant respectively. The average removal efficiency of COD, NH4+-N and TN in effluent was 96.0%,88.3% and 87.4% under the optimal operation conditions respectively. The observed sludge yield was 0.13 mgMLSS/mgCOD, which reduced by 43.5% than MBBR.The MBBR-SA process was simple with a good NH4+-N removal effect, but the CAAC process reduced by 16.0%,76.6% and 22.6% repectively than the MBBR-SA process in respect to effluent COD, MLSS and HRT and observed sludge yield (mgMLSS/mgCOD) of the former was 0.068 far below 0.13 of the latter. Therefore, the CAAC process was chosen as the optimal process to carry out pilot-scale process designment in overall consideration of two process treatment performance to anaerobic effluent.(2) 12 COD degradation strains and 2 heterotroph nitrifying strains were isolated from aerobic sludge by dilution-plate method. By shake flask experiments, each strains performance of COD removal and sludge reduction was investigated. The results were shown that DQ03, DQ04, DQ05, DQ06 and DQ07 were determined as high performance COD removal strains. Two combinations of high performance COD removal strains were obtained by combined strains experiment, which were DQ576 and DQ5736. After adding heterotroph nitrifying strains to DQ576 and DQ5736 respectively, the optimal aerobic degrading strains combination named as DQ5736+HN12 was obtained. Furthermore, the DQ5736+HN12 combination mixed with aerobic sludge according to different proportion, the optimal proportion 3:1 was obtained and the COD removal efficiency was 81.6%.(3) According to the lab-scale CAAC process, the optimal condition (HRT 1.3d) with treating anaerobic effluent from soybean further processing wastewater and pilot-scale condition on the site, the pilot-scale CAAC process mainly consisting of MBBR and AAC fixed bed reactor was designed. Additionally effluent reflux, anoxic zone and anaerobic zone reflux were added to the pilot-scale process. On the basis of reactor intensity and process demand, various kinds of parameters were determined as follow:MBBR height 4.77m, diameter 1m, volume 3.77m3; AAC configuration dimention 4.2m×1.4m×2.7m, volume 15.82m3; reflux tank volume 500L. The computation results also determined liquid transporting pipeline, gas transporting pipeline, packing volume, adiabator with its thickness, sewage pump, blower and so on. Then CAAC process flow diagram, pipeline layout plan, MBBR assembly drawing, AAC reactor assembly drawing and reactor artwork were drew. Finally, the CAAC pilot-scale project was installed in a wastewater treatment plant from a soybean further processing enterprise in Heilongjiang province and will be starting-up using optimal aerobic degraded strains combination. |
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